Municipal authorities are under pressure to improve energy efficiency in order to comply with legislation and environmental objectives. They are also facing calls to address the issue of light pollution, specifically for the sake of night and nature preservation. Yet, at the same time, safety remains a paramount concern. Therefore, research has been conducted on systems that provide light only where and when it is needed. Such systems need to be designed to minimize waste of light without compromising people's safety. For instance, such systems sense activities around individual light sources, adjust the lighting to a maximum level when there is activity and to extremely low levels when there is no activity. Such a system may save up to 80% of energy costs while maintaining safety on the streets.
In such light-on-demand systems, for instance realized with the applicant's LumiMotion, it is required for a node (e.g. a street light) to react to the detection of a street user at a neighboring node located within a certain range. Accordingly, when a node receives a detection message from another node, it needs to know whether to react to this message or not. In other words, the node needs to know whether it is only in hearing range without the need of any action, or whether the message originates from a relevant neighbor node and an action has to be taken (e.g. switching on a lamp). In order to make this distinction, a light-on-demand system generally keeps a table of neighbor nodes and decides, based on the position of the transmitting node in a table, whether it should react or not.
In current systems, the table is created by using the identity of the transmitting node and the averaged RSSI (Received Signal Strength Indication) value of the messages of said transmitting node and ranking the table from strong to weak RSSI. However, the relationship between RSSI values and distances is a questionable one, and it is possible for nodes to be in a wrong position in a table. In certain cases, this may lead to unacceptable behavior of the system and, thus, a correction of the table is required. That means the table has to be manually adapted on-the-spot by a field engineer, for instance using a mobile computer. This adaptation that is required for each node that does not behave as required leads to inconvenience and increased costs.
WO 2007/029186 describes a method for lighting commissioning, which determines a location of a lighting device from the identification number of said lighting device. The location is determined by transmitting an indicator command including the first identification number to the lighting device in question and detecting the response of the lighting device to said indicator command. The lighting device location is then entered manually or automatically on a map.